1. Field of the Invention
The present invention relates to a belt molding for vehicles.
2. Description of Related Art
The following description sets forth the inventor's knowledge of related art and problems therein and should not be construed as an admission of knowledge in the prior art.
As an example of a belt molding for vehicles, an exterior or interior belt molding having a seal lip mounted to a lower edge of a side window opening of a vehicle door can be exemplified. In the belt molding, the seal lip is brought into elastic contact with a surface of a window pane (a side window glass) moved up and down in the door to wipe off water droplets and/or dirt adhered to the window glass (hereinafter, the belt molding may be simply referred to as “belt mold”).
In this kind of a belt molding for vehicles, the seal lip is formed of a soft resin material having elasticity. Therefore, repeated up-and-down movements of the widow pane and/or keeping the window pane closed for a long period of time gradually causes permanent compression set in the resin material, resulting in gradual loosing of the elasticity of the seal lip, which in turn causes a difficulty in returning the seal lip to its original position. As a result, the dirt and/or water droplets wipe-off function of the seal lip deteriorates.
From the viewpoint of preventing the aforementioned drawbacks, there is known a belt molding for vehicles disclosed by, for example, Japanese Unexamined Laid-open Patent Publication No. 2007-131270 (hereinafter referred to as “Patent Document 1”).
In this belt molding, a reinforcing member is embedded therein so as to be positioned from the belt molding main body to the basal end portion of the seal lip, and the material of the seal lip and that of the reinforcing member are set such that the compression set of the combination of the seal lip and the reinforcing member becomes smaller than the compression set of the seal lip itself.
In the belt molding for vehicles disclosed by Patent Document 1, in cases where both the dimension error of the window pane and the dimension error of the peripheral member fall within the central range of the tolerance, after the window pane is moved downward to the window-fully-opened position, and a predetermined time (e.g., a ten and several minutes or more) has passed in a state in which the seal lip is not in contact with the window pane, when the window pane is moved upward up to the window-fully-closed position, the seal lip returns toward the original position side by the creep recovery. Therefore, the wiping operation can be performed in a relatively favorable manner.
However, when the window pane is moved downward from the window-fully-closed position to the window-fully-opened position, and when the window pane is moved upward toward the window-fully-closed position immediately after the downward movement to the window-fully-opened position, a favorable wiping operation cannot be performed in some cases.
That is, a seal lip of a belt molding for vehicles is formed of rubber or thermoplastic elastomer having elasticity, and will be maintained in an elastically deformed state when the seal lip is brought into elastic contact with the window pane surface, which tends to cause creep deformation of the seal lip, especially at the basal end portion thereof. The deformation occurs notably when the weather strip is exposed to temperatures ranging from a higher temperature of 80° C. to a low temperature of −30° C.
In a window pane opened and closed by a normal electric window regulator, the travel time required for the window pane to move from the window-fully-closed position to the window-fully-opened position and the time required for the window pane to move from the window-fully-closed position to the window-fully-opened position are about 2 to 4 seconds, respectively Therefore, the time required for the window pane to move from the window-fully-closed position to the window-fully-opened position and immediately thereafter to move from the window-fully-opened position to the window-fully-closed position is about 4 to 8 seconds. In the case of the manual operation by hand, the time normally falls within the range of 10 to 20 seconds.
In wiping off dirt and/or water droplets adhered to the surface of the window pane by moving the window pane from the window-fully-closed position to the window-fully-opened position and immediately thereafter from the window-fully-opened position to the window-fully-closed position, the creep deformation of the seal lip still remains without being restored. Therefore, the pressing force of the seal lip against the surface of the window pane decreases as compared with the pressing force thereof before occurring the creep deformation, causing deteriorated wiping performance.
In other words, in the weather strip for vehicles disclosed by Patent Document 1 in which the permanent compression set of the combined member of the seal lip and the reinforcing member is set to be smaller than the permanent compression set of the seal lip itself, it is difficult for the seal lip to restore the original shape which is a shape before occurring the creep deformation during the aforementioned short time period.
Such defects can notably occur in part when the distance between the window pane and the belt molding during the movement of the window pane is increased by dimensional variability due to the shape errors of the window pane and the assembly errors of the window pane, or cumulative errors thereof. In a vehicle employing an opening and closing mechanism in which the window pane is displaced toward the belt molding side just before the window is fully closed and displaced in a direction away from the belt molding just after the initiation of the movement of the window pane in the opening direction, the aforementioned drawbacks occur notably all over the window pane.
The description herein of advantages and disadvantages of various features, embodiments, methods, and apparatus disclosed in other publications is in no way intended to limit the present invention. Indeed, certain features of the invention may be capable of overcoming certain disadvantages, while still retaining some or all of the features, embodiments, methods, and apparatus disclosed therein.